Oxygen can afFect the photosynthetic processes in two antagonistic (protective and destructive) ways. The protection is represented by draining off of the electron transport systém, by utilisation of NADPH and ATP, and production of carbon dioxide in the process of photorespiration, oxygen reduction in the Mehler reaction, and also by regeneration of monodehydroascorbate, one of the fmal products of the Mehler-peroxidase reaction. The subsequent building up of the proton gradient in the Mehler and Mehler-peroxidase reactions also helps protéct the photosynthetic apparatus. The production of harmful oxygen radicals is accompanied by the Mehler reaction. This is in contrast to the fact that the Mehler reaction can also protéct the photosynthetic apparatus. Nevertheless, the scavenging mechanisms in plants are efficient enough for protection against the active oxygen species. In some cases the disproportion between the production and scavenging of active oxygen can result in the destruction of thylakoid membrane. Singlet oxygen, another toxic form of oxygen, can also significantly increase the inhibition of photosynthesis in the presence of oxygen. None of these processes works alone or independently, they are in a dynamic equilibrium and each of them contributes to the regulation of photosynthesis.
This study was undertaken to attempt to identify correlations between microsporidial seroprevalence data in man, clinical diseases and groups of people at the risk of HIV/AIDS infection. Groups of patients were selected according to the predilection of members of the genus Encephalitozoon for nervous and kidney tissue. Female prostitutes and alcohol and intravenous drug abusers were selected as groups at risk of HIV/AIDS infections. A total of 401 samples of human sera were examined for the presence of antimicrosporidial IgG antibodies by ELISA test with a titre of 600 considered borderline positivity. The highest occurrence of antimicrosporidial antibodies was found in the groups of alcohol abusers (16 % from 43 patients), intravenous drug abusers (11 % from 9 patients) and prostitutes (10 % from 80 women) for E. cuniculi antigen and in the groups of psychiatric patients (14 % from 44 patients), malaria patients (11 % from 38 patients) and alcohol abusers (7 % from 43 patients) for E. hellem antigen. The occurrence of specific antibodies of the six examined diagnostic units (glomerulonephritis chronica, pyelonephritis chronica, schizophrenia, dementia, multiple sclerosis and cerebral stroke) was statistically significant only in patients with pyelonephritis chronica and dementia (p < 0.05), No cases of microsporidial infection were found among the female prostitutes by parasitological examination, although one case of giardiasis was identified. Sera of patients with high anti-/:, cuniculi and anti-fc'. hellem antibodies (titres in ELISA of 600 and above) were confirmed by Western blot using E. cuniculi and E. hellem polypeptides, respectively. These results suggest that the examined patients could show residual antibodies from past or latent infections.
Three-spined stickleback (Gasterosteus aculeatus L.), ninc-spined stickleback (Pungitius pungitius (L.)) and flounder 0Platichthys flesus (L.)) are widespread teleosts, which all have behaviours involving migration between freshwater and brackish/sea water environments. Their importance in dispersal of the freshwater monogenean Gyrodactylus salaris Malmberg, 1957, which causes heavy losses of Atlantic salmon (Salmo salar L.) parr in infected Norwegian rivers, was tested indirectly by their susceptibility and resistance to the parasite in laboratory experiments. Gyrodactylus salaris attached to the three fish species, but no parasite reproduction was observed. The infections were eliminated alter a maximum of 3 days on flounder, 6 days on nine-spined stickleback, and 8 days on three-spined stickleback. Thus these fishes are innately resistant to G. salaris, and are therefore of no importance concerning the population dynamics of G. salaris in freshwater systems. However, attachment of parasites indicates that these fish species may function as transport hosts, and theoretically play a part in the dispersal of G. salaris in nature.
A strongly recommended conclusion in sociology about trends in class inequality has been summarised by Goldthorpe as a high degree of 'temporal constancy and cross-national communality'. This conclusion, here called 'the stability thesis', was first challenged by Ringen in 1987 and again, on more methodological grounds, by Ringen and Hellevik in two papers published in 1997. These challenges resulted in a process of debate and reassessment. It is now possible to sum up and conclude. The stability thesis rests on empirical results from odds-ratio readings of mobility table data. The authority of this methodology is re-examined in terms of normative significance and statistical validity. Mobility table data which have generated stability thesis findings are reanalysed with the standard gini-index methodology in the study of inequality, then yielding different findings which contradict the stability thesis. The main conclusion is that the stability thesis can now be considered overturned. Keywords: social inequality, social justice, social reform, class analysis, social stratification.
The anterior jejunum from common vole naturally infected with Giardia microti (Kofoid et Christiansen, 1915) was examined by ТЕМ and compared with the anterior jejunum from control (metronidazole-treated, Giardia-free) common voles (Pallas, 1778). Giardia microti infection resulted in significant diffuse shortening of microvilli and significant greater microvillous diameters. In addition, deformations of the microvilli were observed at the margin of the ventral disc. The microvilli attached to the lateral crest of the ventral disc were vesiculated with a disorganised filamentous core and contained whorled structures resembling “myelin-like figures”. The findings are discussed in context of the Giardia-epithelial cell interaction.